Color-sensitized photographic material



-' umrso srA- rss PATENT OFFICE.

* mun: ronsrm amrwrcx, or mmwoosi AND our moon, or Lennon, ENG- LAND, ASSIGNORS TO ILFQRD LIMITED, OF ILFORHJ, ENGLAND.-

coLon ssnsrrxznn Pno rpemmc MJATERIAL.

a No Drawing.

To all whom it I Be it known that we, FRaiIK Fons rnn RENWIOK, a subject of the Kin ofnEngland, and OLAF BLooH, asubject 0 the'Kingjof England, residing at Brentwood,' in Essex England, and London, in England, respec'-" tively, have invented certain new and-useful Improvements in Color-sensitized, Photographic Materials, of which the following is a specification. p This invention is for improvements in or relating to color sensitized photographic materials, and has for its object to provide material which shall havefeither a difierent,

or greater color-sen'sitiveness than has heretofore been obtainable. a

In our concurrent patent application ,Serial N o. 263,591,,we have described means for obtaining a plate-having either a different or a greater color-sensitiveness than those at present existingby means of using,

a dye of the auramin' class which is define in the said specificationas the auramin o1 iminodiphenyl methane class, e. substitution der vatives of benzophenoneimid.

"The chemical formula for the rincipal member of the class is (N(CH C H,)

(lax-NH, and it is to be understood or both of the two dimethylamido groups may be replaced by hydrogen or organic radicals, and that any one or more of theremaining nine hydrogen'atoms in this typical compound may be replaced by another atom or group such as chlorin, the ethyl group and others of this class.

the amido group, toform new dyes According "to the present invention, the

colorsensitized material comprises a light- SeIlSltlVG emuls on containing a dye of ,the

auramin class as defined, together with one] ormore dyes-of the isocyanin class, such for example as the pinacyanol, obtained by heating an alcoholic solution of. quinaldin ethiodid, with or vwithoiitquinolin ethiodid,

i added to that of the auramin class depends. upon the effect requ red.

with aqueous sodium 'hydrat in presence of formaldehyde. The sensitized material so produced possesses valuable photographic properties such as'improved color-sensitivenes's' with freedom from fog, and good keepin properties. v a

he choice of the .isocyanin dye or dyes For example, with the above lsocyanin dye green sensitiveness 1s obtamed and also new fl. is to be sensitized separate dyes,

that one auramin in the emulsion as a yellow filter improved red and sensitivenessto deep red is produced which i ppltfound with this pinacyanol alone. e

lar to those already employed for color-sen; sitizing materials, for example if a dry plate by the bathing process, it maybe immersed for three or four minutes in a bath composed of 100,000 cos. of water, 2 grms. of the dyeof the auramin class, and 2 grms. of the isocyanin dye. i f If the dyes are to be mixed with the melted emulsion, then -.from .005 to .025 grms. of each dye is used per litenof. emulsion.

As is well-known when two dyes are used together the usual effect is to produce a plate havin features corresponding -to both dyes 'tl'l0l1g1 frequently the, effect of-one or the other is marked diminished.- However, w1th combinations of auramin and the above 9 mentioned pinacyanol and other combinations of the same two classes, the character of the sensitiveness is changed and improved, it not being such as "would be expected, but usually different from and much greaterthan the sum of the effects of the moreover other valuable hotographic qualities are introduced 01:

Spe'cIfication of Lette'rs'Patent. Patented Man 22, 1921. Application filed November 21, ie a. SeriaI'No. 263,592.

proportions of the dyes used are simi- I improved, 0. g. cleanliness, good keeping 7 properties. a

It will be understood that in the bathing process the usual variations, consist in the substitution of, some alcohol for some of the water and the additionof some ammonia be made.- v has previously been proposed to ,use

in the manufactureof a self-screened or non-filter orthbchromatic plate, but this procovery of the isocyanin dyes and its sensitizing action wvas then unknown,=moreover, the dye was used in such quantity asto, and solely for the purpose of reducing the action of blue light on the plate in the same way as tartrazin and other yellow dyes are used posal was made prior to the date of disdye of the auramin or iminodiphenyl methane class in sufiiciently large-proportions, for example 20, gm to the 100,000

ccs. bath instead of 2 grms. or .25 grms. per.

liter of emulsion instead of .005 to .025 guns. to operate as a screen as well as a -sens1ti'zer,as it is found that when such dye is thus employed in' conjunction with the isocyanin dyes, it still markedly improves the color sensitiveness conferred, as well as as pinacyanols,

having :1 screening effect.

The term isocyanins in the spec1fica tion and'claims is to be interpreted in the same sense as it was used in the early days which is obtained in one wa by the action of alkali in the presence 0 formaldehyde on quinaldin ethiodid.

- The various terms used inthe claims are used in accordance with the definitions herein" 'ven, which definitions represent their for example 'quinaldin-blue,v

imam

accepted meaning both scientifically and chemically.

Whatwe claim as our'invention and de" sire to secure by Letters Patent is 1. A color sensitizing material, comprising a light sensitive emulsion containing a dye of the ,7 auramin or iminodiphenyl methane class, together with a dye of the isocyanin class, substantially as described.

2. A color sensitizing material substantially as described comprising a light sensitive emulsion containin a dye of the auramin, or iminodipheny ethane class, together with that isocyanin dye which is obtained when an alcoholic solution of quinaldin ethiodid is heated with aqueous sodium hydrate in presence of formaldehyde.

In testimony whereof we have signed our,

names to this specification in the presence of two subscribing witnesses.

FRANK FORSTER RENWICK. OLAF BLOCH.

Witnesses: l

' HAYWARD,

HARRY L. LEIDYL. 

